This plugin lets you get images from the Planet Labs API, by performing searches for images that intersect with the extent of the map window.
It is a product from Planet Explorers program (https://www.planet.com/explorers/), it is not an official Planet Labs's plugin.
You need a key from Planet Labs in order to use this plugin.
This plugin will be create polygon layer (Catalog of images) from intersect with the extent of the map window.
With this plugin, you can download full images, visual or analytic, thumbnail images or add TMS images.
See presentation in http://pt.slideshare.net/LuizMotta3/planetlabs-explorer-qgisplugin